1. Field of the Invention
The present invention relates to an automobile fuel tank with a damper layer thereon, and a method of manufacturing such a damper layer.
2. Description of the Relevant Art
Some automobile fuel tanks have damper layers of rubber or the like bonded to their outer surface for protecting the tanks from shocks. One known damper layer is attached to cover the entire surface of a fuel tank to protect the same, as disclosed in Japanese laid-open utility model publication No. 61-17163, for example.
Generally, however, damper layers are attached to only local regions of the paint-coated outer surface of a fuel tank which tend to be brought into abrasive or hitting contact with an automobile body. Such damper layers attached to local fuel tank surface regions may comprise rubber sheets that are bonded to the fuel tank surface by a subsequently applied adhesive or damper sheets that are bonded to the fuel tank surface by adhesive layers carried on the respective damper sheets. When the damper sheets are to be bonded, peel-off liner sheets are peeled off the adhesive layers to allow the adhesive layers to be applied to the fuel tank surface. When rubber sheets are bonded to the fuel tank surface, the entire attaching process has to be carried out manually because the positions of the rubber sheets need to be varied depending on the shape and type of the fuel tank. Consequently, the attaching process is not highly efficient, and hence the rate of production of fuel tanks with damper layers is poor.
According to still another damper layer design as disclosed in Japanese laid-open utility model publication No. 61-78727 or Japanese laid-open patent publications Nos. 62-204029 and 1-199030, a liquid damper material is coated on the surface of a fuel tank and subsequently allowed to set into a damper layer. In each of these publications, the liquid damper material is composed of a high-polymer viscous substance of synthetic rubber or natural rubber, a softener of vegetable oil or fatty oil, a tackifier of xylene, phenol, or the like, and either elastic particles of natural rubber, nitrile rubber, or the like, or a thermoplastic elastomer such as thermoplastic polyurethane or the like. In use, the liquid damper material is heated up to 140.degree. C..about.170.degree. C., and applied as a hot melt to a fuel tank surface. The liquid damper material can quickly be applied as a hot melt to the fuel tank surface through a coating nozzle of a coating apparatus without manual intervention. However, inasmuch as the overall hot melt supply line leading up to the coating nozzle of the coating apparatus must be controlled in temperature, the coating nozzle is complex and expensive.